Writing a Vertex Shader to handle a stateless particle system

Hi, so recently I read this article

http://www.gamasutra.com/view/feature/130535/building_a_millionparticle_system.php?print=1

and was curious to see if I could try writing a vertex shader in unity that would allow particles to be simulated based on some initial starting values (position, velocity, rotational velocity, etc). However, I'm unsure how I'd set up the starting values. Originally I thought I could just make them properties of the shader, but wouldn't that mean that each particle would end up getting a different material even if they shared a texture, killing batching? There must be SOME way to do this correctly, but I'm having trouble finding it.

Any help pointing me in the right direction would be appreciated!

 

Bump . . . anyone have any ideas?